The problem comes from the variation of the
large avalanche in which Black plays below.

Large avalanche, Black turns outside

Jonathan Cano: the normal move for White here is
a. In
Dictionary of Basic Joseki
Ishida Yoshio says at b is a mistake.

A mistake by White

Jonathan Cano: Ishida says " seems vulgar
but it avoids complications and guarantees a favorable
result. For his part White has no choice but to make
the vulgar ataris of and . White answers at a or
b."

A mistake by White, continuation b.1

Jonathan Cano: Here is the continuation when White plays
at b in the diagram above.

A mistake by White, continuation b.2

A mistake by White, continuation b.3

Jonathan Cano: After Black 2 Ishida says Black a and b are miai so White is hopeless.

How professionals play

Checking MasterGo, I found that professionals actually play (4 games out of 4) here rather than at as Ishida proposes. After , Black plays either a or b, after which the various groups in the diagram fight things out.

Large Avalanche Turn Outward Problem last edited by CharlesMatthews on July 1, 2003 - 09:15